|Researched by||Nicola White||Refereed by||Dr Stefan Kraan|
|Other common names||-||Synonyms||-|
The bladder wrack Fucus vesiculosus is a large brown algae, common on the middle shore. It can be found in high densities living for about 4-5 years (S. Kraan, pers. comm.). Under sheltered conditions, the fronds have been known to grow up to 2 m in Maine, America (Wippelhauser, 1996).
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|Phylum||Ochrophyta||Brown and yellow-green seaweeds|
|Typical abundance||High density|
|Male size range||Up to 1.5m|
|Male size at maturity||15-20cm|
|Female size range||15-20cm|
|Female size at maturity|
|Characteristic feeding method||Autotroph|
|Typically feeds on|
|Is the species harmful?||No|
Air bladders or vesicles are produced annually to make the frond float upwards when immersed, except at highly exposed coasts where no air bladders are produced (S. Kraan, pers. comm.). Fucus vesiculosus supports few colonial organisms, but provides substratum and shelter for the tube worm Spirorbis spirorbis, herbivorous isopods, such as Idotea, and surface grazing snails, such as Littorina obtusata.
The growth rate of fucoids is known to vary both geographically and seasonally (Lehvo et al., 2001). Relative growth rate can vary from 0.05-0.14 cm/day depending on temperature and light conditions (S. Kraan, pers. comm.). The increase in growth rate for Fucus vesiculosus at 10, 12.5 and 15 °C was found to be, on average, 280% higher than it was at 7 °C (Strömgren, 1977). In the northern Baltic, the highest relative growth rate of vegetative branches for Fucus vesiculosus was observed in the summer (up to 0.7% / day ) compared to winter growth (less than 0.3% / day). In Sweden, growth rates of 0.7-0.8 cm / week were reported over the summer months of June and August (Carlson, 1991).
Growth rate can also vary with exposure. In Scotland, Fucus vesiculosus at Sgeir Bhuidhe, a very exposed site, grew about 0.31 cm / week whereas plants at Ascophyllum Rock grew an average of 0.68 cm / week (Knight & Parke, 1950). The proportion of energy allocated between vegetative and reproductive growth also varies throughout the year. In the northern Baltic, reproductive branches experienced a peak in growth rate in mid April where the relative growth rate was almost 0.1% / day (Lehvo et al., 2001).
|Physiographic preferences||Open coast, Strait / sound, Sea loch / Sea lough, Ria / Voe, Estuary, Enclosed coast / Embayment|
|Biological zone preferences||Mid eulittoral, Upper eulittoral|
|Substratum / habitat preferences||Artificial (man-made), Bedrock, Cobbles, Gravel / shingle, Large to very large boulders, Pebbles, Small boulders|
|Tidal strength preferences||Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Strong 3 to 6 knots (1.5-3 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.)|
|Wave exposure preferences||Moderately exposed, Sheltered, Very sheltered|
|Salinity preferences||Full (30-40 psu), Reduced (18-30 psu), Variable (18-40 psu)|
|Depth range||Not relevant|
|Other preferences||No text entered|
|Migration Pattern||Non-migratory / resident|